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Papers by Maximiliano Mereles
European Spine Journal, 2015
XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential ... more XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential risk of injuring the lumbar plexus nerves. Intraoperative neurophysiological monitoring (IOM) is, therefore, critical in this kind of procedures; nevertheless, there were some reports of neural damage. Purpose To determine the effectiveness of a new protocol for IOM during XLIF. Materials and methods This prospective, nonrandomized, institutional review board-approved study enrolled adult patients of both sexes undergoing XLIF at the Italian Hospital of Buenos Aires between 2012 and 2014. Preoperative and immediate postoperative neurological examinations were carried out, paying special attention to lumbar plexus motor and sensory territories. IOM included EMG and transpsoas stimulation, considering the territories of every motor and sensory branch of the lumbar plexus. Results 107 patients (133 lumbar levels) were evaluated. Reproducible responses were obtained in the collateral and terminal branches of the lumbar plexus, which were well preserved. No patient (0 %) had new motor postoperative deficits. Nineteen (17.75 %) patients had minor and transient sensory symptoms, lasting less than a month. One patient (0.93 %) had longer duration of sensory complaints (3 months). Conclusion A detailed IOM of lumbar plexus branches can determine in real time the proximity of intrapsoas nerves during XLIF.
303 Abstract The minimally-invasive lateral approach of the lumbar spine for interbody fusion is ... more 303 Abstract The minimally-invasive lateral approach of the lumbar spine for interbody fusion is a relatively new technique and has got promising results in patients with different lumbar spine conditions. It is a safe technique that provides the spine with appropriate structural support between vertebral endplates, it can correct deformities on coronal and sagittal planes and conduct indirect decompression of the spinal canal with preservation of the posterior elements. Over the past few years the evidence that backs this technique has been increasing and diversifying, there are reports on new indications and midand long-term results. The aim of this work is to describe the surgical procedure step by step with its variant procedures as we conduct it at the Centers we work at, and to point out related current concepts based on a bibliographic revision.
Revista Española de Cirugía Ortopédica y Traumatología (English Edition)
Abstract Introduction Lumbar disc hernias are a common cause of spinal surgery. Hernia recurrence... more Abstract Introduction Lumbar disc hernias are a common cause of spinal surgery. Hernia recurrence is a prevalent complication. Objective To analyse the risk factors associated with hernia recurrence in patients undergoing surgery in our institution. Materials and methods Lumbar microdiscectomies between 2010 and 2014 were analysed, patients with previous surgeries, extraforaminales and foraminal hernias were excluded. Patients with recurrent hernia were the case group and those who showed no recurrence were the control group. Results 177 patients with lumbar microdiscectomy, of whom 30 experienced recurrence (16%), and of these 27 were reoperated. Among the risk factors associated with recurrence, we observed a higher rate of disc height, higher percentage of spinal canal occupied by the hernia and presence of degenerative facet joint changes; we observed no differences in sex, body mass index or age. Discussion Previous studies show increased disc height and young patients as possible factors associated with recurrence. Conclusion In our series we found that the higher rate of disc height, the percentage of spinal canal occupied by the hernia and degenerative facet joint changes were associated with hernia recurrence.
Coluna/Columna
Objective Primary and secondary spine tumors occur frequently and treating them surgically has ga... more Objective Primary and secondary spine tumors occur frequently and treating them surgically has gained prominence. The objective of this study was to evaluate the outcomes and complications in a series of patients with primary and secondary vertebral tumors treated by en bloc vertebral resection. Methods A retrospective review of the patients who underwent en bloc vertebral resection between 2004 and 2017 was conducted. Results During the study period, 16 patients underwent en bloc vertebral resection. They were divided into primary tumor and metastatic tumor groups, 11 being primary tumors and 5 metastatic tumors. The average follow-up period was 95 months (3-156 months). The patients were treated by the same surgical team and the analysis was carried out by an independent observer. Conclusion In this case series, the results where comparable to those reported in the literature in terms of complications, survival, recurrence and neurological status. It is a demanding surgical techni...
International Journal of Radiology & Radiation Therapy
Introduction:Intradiscal gas generated from degenerative disc phenomena is called vacuum or pneum... more Introduction:Intradiscal gas generated from degenerative disc phenomena is called vacuum or pneumodisc. It is mainly caused by primary intervertebral osteochondrosis. It has a high prevalence in elderly population. The migration of this gas to the spinal canal can generate cord or root compression and result in radiculalgia or canal stenosis. We describe two cases of radicular pain due to aerial pseudocyst diagnosed and treated in our center and review the available reports. Conclusion: The radicular pain originated by epidural gas-containing pseudocyst is an unusual diagnosis, for which there is no consensus regarding the diagnosis methods and its treatment. We consider computed tomography to be the most specific study and we suggest surgical resolution by decompression and microreseccion of the cyst when conservative treatment is not effective.
![Research paper thumbnail of Osteosarcoma “tipo osteoblastoma” de columna cervical. A propósito de un caso. [Osteoblastoma like osteosarcoma of the cervical spine]](https://attachments.academia-assets.com/74089612/thumbnails/1.jpg)
](Revista de la Asociación Argentina de Ortopedia y Traumatología
El osteosarcoma “tipo osteoblastoma”, una variante menos agresiva del osteosarcoma, es una enferm... more El osteosarcoma “tipo osteoblastoma”, una variante menos agresiva del osteosarcoma, es una enfermedad poco frecuente y representa un desafío diagnóstico tanto clínico como histopatológico. Se han publicado escasos reportes de casos de este tumor.Presentamos a un paciente de 16 años con un osteosarcoma “tipo osteoblastoma” localizado en la columna cervical. La biopsia ósea bajo tomografía reveló una lesión con un patrón de crecimiento permeativo, con sospecha de osteosarcoma “tipo osteoblastoma”. Se realizó una espondilectomía total en bloque mediante un doble abordaje. Se describen el caso clínico, la secuencia diagnóstica, la técnica quirúrgica y el seguimiento a 10 años. ABSTRACT Osteoblastoma-like osteosarcoma; a less aggressive variant of osteosarcoma;is a rare entity and represents a clinical and histopathological diagnostic challenge. We have found few reports of cases of this tumor in the literature. In this case we describe an osteoblastoma-like osteosarcoma located in the c...
![Research paper thumbnail of Artrodesis intersomática lateral de columna lumbar. Técnica quirúrgica y conceptos actuales.[Lateral lumbar interbody fusion. Surgical technique and current concepts]](https://attachments.academia-assets.com/74089610/thumbnails/1.jpg)
](Revista de la Asociación Argentina de Ortopedia y Traumatología
El abordaje lateral mínimamente invasivo de columna lumbar para la artrodesis intersomática es un... more El abordaje lateral mínimamente invasivo de columna lumbar para la artrodesis intersomática es una técnica relativamente nueva y ha conseguido resultados prometedores en los pacientes con diferentes patologías de la columna lumbar. Es una técnica segura que proporciona un adecuado soporte estructural entre los platillos vertebrales, puede corregir la deformidad en los planos coronal y sagital, y ejercer una descompresión indirecta del canal raquídeo respetando los elementos posteriores. La evidencia sobre esta técnica ha ido creciendo y diversificándose en los últimos años, se han comunicado nuevas indicaciones, y resultados a mediano y largo plazo. El propósito de este trabajo es detallar el procedimiento quirúrgico paso a paso, con sus variantes tal como lo realizamos en nuestros Centros, y puntualizar los conceptos actuales basados en una revisión bibliográfica. Palabras clave: Artrodesis intersomática; vía anterior; fusión intersomática lumbar lateral; fusión intersomática extremo lateral; abordaje lateral de columna; conceptos actuales. Nivel de Evidencia: IV Lateral lumbar interbody fusion. Surgical technique and current concepts
European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, Jan 23, 2018
The authors describe a percutaneous technique to treat advanced degenerative disk disease in elde... more The authors describe a percutaneous technique to treat advanced degenerative disk disease in elderly patients. A step-by-step technical description based on our experience in selected cases. Postoperative imaging results are presented as well as indications and recommendations. Percutaneous discoplasty can result as an alternative minimal invasive strategy for the treatment of advanced degenerative disk disease.
Global Spine Journal, 2015
Study Design: Retrospective study. Objective: Spinal metastasis can produce pain, deformity, neur... more Study Design: Retrospective study. Objective: Spinal metastasis can produce pain, deformity, neurological compromise and can decrease life expectancy. Surgical management is usually indicated for pain control, neurological decompression, and to avoid deformity progression. Tokuhashi et al created a scoring system to estimate survival and stratify surgical treatment based on established parameters. Our objective was to evaluate the usefulness of Tokuhashi scoring (TS) system by comparing the predicted and real survival times and analyze the survival time according to the type of tumor. Methods: From 2004 to 2014, 105 patients with vertebral metastasis who underwent surgical treatment were enrolled and retrospectively analyzed. Preoperative TS was performed in all cases. Patients were classified into 3 groups according to TS; group 1 (TS 0-8), group 2 (TS 9-11), and group 3 (TS 12-15). Patients' average age was 61.5 years, main primary tumor site were as follows: kidney (23%), lung (19%), and breast (18%). Results: The Tokuhashi general concordance was 67.6%. Per group concordance was as follows: group 1 80%, in group 2, only 33% of concordance was observed. In group 3, 100% of concordance was observed. In group 2, the most common primary sites were breast and kidney and the mean survival was 20 and 22.3 months, respectively, both longer than that expected for this group. Conclusions: Tokuhashi concordance was acceptable in our study, particularly in lower and higher scores. The lesser concordance observed in group 2 (33.3%) was observed in almost all tumors. For our practice, TS constitutes an acceptable tool to define survival, particularly in lower and higher scores.
European Spine Journal, 2015
XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential ... more XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential risk of injuring the lumbar plexus nerves. Intraoperative neurophysiological monitoring (IOM) is, therefore, critical in this kind of procedures; nevertheless, there were some reports of neural damage. To determine the effectiveness of a new protocol for IOM during XLIF. This prospective, nonrandomized, institutional review board-approved study enrolled adult patients of both sexes undergoing XLIF at the Italian Hospital of Buenos Aires between 2012 and 2014. Preoperative and immediate postoperative neurological examinations were carried out, paying special attention to lumbar plexus motor and sensory territories. IOM included EMG and transpsoas stimulation, considering the territories of every motor and sensory branch of the lumbar plexus. 107 patients (133 lumbar levels) were evaluated. Reproducible responses were obtained in the collateral and terminal branches of the lumbar plexus, w...
European Spine Journal, 2015
XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential ... more XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential risk of injuring the lumbar plexus nerves. Intraoperative neurophysiological monitoring (IOM) is, therefore, critical in this kind of procedures; nevertheless, there were some reports of neural damage. Purpose To determine the effectiveness of a new protocol for IOM during XLIF. Materials and methods This prospective, nonrandomized, institutional review board-approved study enrolled adult patients of both sexes undergoing XLIF at the Italian Hospital of Buenos Aires between 2012 and 2014. Preoperative and immediate postoperative neurological examinations were carried out, paying special attention to lumbar plexus motor and sensory territories. IOM included EMG and transpsoas stimulation, considering the territories of every motor and sensory branch of the lumbar plexus. Results 107 patients (133 lumbar levels) were evaluated. Reproducible responses were obtained in the collateral and terminal branches of the lumbar plexus, which were well preserved. No patient (0 %) had new motor postoperative deficits. Nineteen (17.75 %) patients had minor and transient sensory symptoms, lasting less than a month. One patient (0.93 %) had longer duration of sensory complaints (3 months). Conclusion A detailed IOM of lumbar plexus branches can determine in real time the proximity of intrapsoas nerves during XLIF.
303 Abstract The minimally-invasive lateral approach of the lumbar spine for interbody fusion is ... more 303 Abstract The minimally-invasive lateral approach of the lumbar spine for interbody fusion is a relatively new technique and has got promising results in patients with different lumbar spine conditions. It is a safe technique that provides the spine with appropriate structural support between vertebral endplates, it can correct deformities on coronal and sagittal planes and conduct indirect decompression of the spinal canal with preservation of the posterior elements. Over the past few years the evidence that backs this technique has been increasing and diversifying, there are reports on new indications and midand long-term results. The aim of this work is to describe the surgical procedure step by step with its variant procedures as we conduct it at the Centers we work at, and to point out related current concepts based on a bibliographic revision.
Revista Española de Cirugía Ortopédica y Traumatología (English Edition)
Abstract Introduction Lumbar disc hernias are a common cause of spinal surgery. Hernia recurrence... more Abstract Introduction Lumbar disc hernias are a common cause of spinal surgery. Hernia recurrence is a prevalent complication. Objective To analyse the risk factors associated with hernia recurrence in patients undergoing surgery in our institution. Materials and methods Lumbar microdiscectomies between 2010 and 2014 were analysed, patients with previous surgeries, extraforaminales and foraminal hernias were excluded. Patients with recurrent hernia were the case group and those who showed no recurrence were the control group. Results 177 patients with lumbar microdiscectomy, of whom 30 experienced recurrence (16%), and of these 27 were reoperated. Among the risk factors associated with recurrence, we observed a higher rate of disc height, higher percentage of spinal canal occupied by the hernia and presence of degenerative facet joint changes; we observed no differences in sex, body mass index or age. Discussion Previous studies show increased disc height and young patients as possible factors associated with recurrence. Conclusion In our series we found that the higher rate of disc height, the percentage of spinal canal occupied by the hernia and degenerative facet joint changes were associated with hernia recurrence.
Coluna/Columna
Objective Primary and secondary spine tumors occur frequently and treating them surgically has ga... more Objective Primary and secondary spine tumors occur frequently and treating them surgically has gained prominence. The objective of this study was to evaluate the outcomes and complications in a series of patients with primary and secondary vertebral tumors treated by en bloc vertebral resection. Methods A retrospective review of the patients who underwent en bloc vertebral resection between 2004 and 2017 was conducted. Results During the study period, 16 patients underwent en bloc vertebral resection. They were divided into primary tumor and metastatic tumor groups, 11 being primary tumors and 5 metastatic tumors. The average follow-up period was 95 months (3-156 months). The patients were treated by the same surgical team and the analysis was carried out by an independent observer. Conclusion In this case series, the results where comparable to those reported in the literature in terms of complications, survival, recurrence and neurological status. It is a demanding surgical techni...
International Journal of Radiology & Radiation Therapy
Introduction:Intradiscal gas generated from degenerative disc phenomena is called vacuum or pneum... more Introduction:Intradiscal gas generated from degenerative disc phenomena is called vacuum or pneumodisc. It is mainly caused by primary intervertebral osteochondrosis. It has a high prevalence in elderly population. The migration of this gas to the spinal canal can generate cord or root compression and result in radiculalgia or canal stenosis. We describe two cases of radicular pain due to aerial pseudocyst diagnosed and treated in our center and review the available reports. Conclusion: The radicular pain originated by epidural gas-containing pseudocyst is an unusual diagnosis, for which there is no consensus regarding the diagnosis methods and its treatment. We consider computed tomography to be the most specific study and we suggest surgical resolution by decompression and microreseccion of the cyst when conservative treatment is not effective.
Revista de la Asociación Argentina de Ortopedia y Traumatología
El osteosarcoma “tipo osteoblastoma”, una variante menos agresiva del osteosarcoma, es una enferm... more El osteosarcoma “tipo osteoblastoma”, una variante menos agresiva del osteosarcoma, es una enfermedad poco frecuente y representa un desafío diagnóstico tanto clínico como histopatológico. Se han publicado escasos reportes de casos de este tumor.Presentamos a un paciente de 16 años con un osteosarcoma “tipo osteoblastoma” localizado en la columna cervical. La biopsia ósea bajo tomografía reveló una lesión con un patrón de crecimiento permeativo, con sospecha de osteosarcoma “tipo osteoblastoma”. Se realizó una espondilectomía total en bloque mediante un doble abordaje. Se describen el caso clínico, la secuencia diagnóstica, la técnica quirúrgica y el seguimiento a 10 años. ABSTRACT Osteoblastoma-like osteosarcoma; a less aggressive variant of osteosarcoma;is a rare entity and represents a clinical and histopathological diagnostic challenge. We have found few reports of cases of this tumor in the literature. In this case we describe an osteoblastoma-like osteosarcoma located in the c...
Revista de la Asociación Argentina de Ortopedia y Traumatología
El abordaje lateral mínimamente invasivo de columna lumbar para la artrodesis intersomática es un... more El abordaje lateral mínimamente invasivo de columna lumbar para la artrodesis intersomática es una técnica relativamente nueva y ha conseguido resultados prometedores en los pacientes con diferentes patologías de la columna lumbar. Es una técnica segura que proporciona un adecuado soporte estructural entre los platillos vertebrales, puede corregir la deformidad en los planos coronal y sagital, y ejercer una descompresión indirecta del canal raquídeo respetando los elementos posteriores. La evidencia sobre esta técnica ha ido creciendo y diversificándose en los últimos años, se han comunicado nuevas indicaciones, y resultados a mediano y largo plazo. El propósito de este trabajo es detallar el procedimiento quirúrgico paso a paso, con sus variantes tal como lo realizamos en nuestros Centros, y puntualizar los conceptos actuales basados en una revisión bibliográfica. Palabras clave: Artrodesis intersomática; vía anterior; fusión intersomática lumbar lateral; fusión intersomática extremo lateral; abordaje lateral de columna; conceptos actuales. Nivel de Evidencia: IV Lateral lumbar interbody fusion. Surgical technique and current concepts
European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, Jan 23, 2018
The authors describe a percutaneous technique to treat advanced degenerative disk disease in elde... more The authors describe a percutaneous technique to treat advanced degenerative disk disease in elderly patients. A step-by-step technical description based on our experience in selected cases. Postoperative imaging results are presented as well as indications and recommendations. Percutaneous discoplasty can result as an alternative minimal invasive strategy for the treatment of advanced degenerative disk disease.
Global Spine Journal, 2015
Study Design: Retrospective study. Objective: Spinal metastasis can produce pain, deformity, neur... more Study Design: Retrospective study. Objective: Spinal metastasis can produce pain, deformity, neurological compromise and can decrease life expectancy. Surgical management is usually indicated for pain control, neurological decompression, and to avoid deformity progression. Tokuhashi et al created a scoring system to estimate survival and stratify surgical treatment based on established parameters. Our objective was to evaluate the usefulness of Tokuhashi scoring (TS) system by comparing the predicted and real survival times and analyze the survival time according to the type of tumor. Methods: From 2004 to 2014, 105 patients with vertebral metastasis who underwent surgical treatment were enrolled and retrospectively analyzed. Preoperative TS was performed in all cases. Patients were classified into 3 groups according to TS; group 1 (TS 0-8), group 2 (TS 9-11), and group 3 (TS 12-15). Patients' average age was 61.5 years, main primary tumor site were as follows: kidney (23%), lung (19%), and breast (18%). Results: The Tokuhashi general concordance was 67.6%. Per group concordance was as follows: group 1 80%, in group 2, only 33% of concordance was observed. In group 3, 100% of concordance was observed. In group 2, the most common primary sites were breast and kidney and the mean survival was 20 and 22.3 months, respectively, both longer than that expected for this group. Conclusions: Tokuhashi concordance was acceptable in our study, particularly in lower and higher scores. The lesser concordance observed in group 2 (33.3%) was observed in almost all tumors. For our practice, TS constitutes an acceptable tool to define survival, particularly in lower and higher scores.
European Spine Journal, 2015
XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential ... more XLIF is an increasingly popular procedure that requires traversing the psoas, with the potential risk of injuring the lumbar plexus nerves. Intraoperative neurophysiological monitoring (IOM) is, therefore, critical in this kind of procedures; nevertheless, there were some reports of neural damage. To determine the effectiveness of a new protocol for IOM during XLIF. This prospective, nonrandomized, institutional review board-approved study enrolled adult patients of both sexes undergoing XLIF at the Italian Hospital of Buenos Aires between 2012 and 2014. Preoperative and immediate postoperative neurological examinations were carried out, paying special attention to lumbar plexus motor and sensory territories. IOM included EMG and transpsoas stimulation, considering the territories of every motor and sensory branch of the lumbar plexus. 107 patients (133 lumbar levels) were evaluated. Reproducible responses were obtained in the collateral and terminal branches of the lumbar plexus, w...